Thermoradiant heating unit



E. F. WAcH THERMORADIANT HEATING UNIT Filed Oct. 4, 1935 June 22, 1937.

Wach

Patented an. 22, 1931 UNITED STATES PATEN OFFICE 2 Claims.

This invention relates to electric heating units and particularly to oneusable for heating edifices of all kinds, vehicles, boats, airplanesetc., poultry incubators and brooder houses, and for other commercialuses where a mild controlled heat is required at an economical cost andwhich can be produced from electrical energy.

It is of course well to note that in any of its forms a resistanceelement, or a conductor of 10 electricity, dissipates a certain amountof heat proportionate to the current strength and resistance of thematerial used for the element.

This causes what is known as a heat loss" of energy which in myinvention is scientifically dissipated into the surrounding space byradiation to impart its heat into the air. Ordinarily this radiatingaction takes place radially in all directions from the center ofemission, which in the case of an electric wire, is the center of thecross sectional area of the same.

By the use of the various layers comprising my unit, this heat loss iseconomically directed and dissipated to a space to be utilized in anefficient manner for heating-purposes.

The higher the temperature of the body or wire the more intense ingeneral is the heat radiated. This is known as thermal radiation.

It is the main object of my invention to provide an electric heatingdevice or unit suitable for the purposes recited above. which is soconstructed that while the electric heating element itself is completelyinsulated so that a fine resistant and dielectric unit is formed whicheliminates all fire and shock hazards, the maximum amount of heat lossor thermal radiation is harnessed and transmitted in the desireddirection for utilization in heating the room space, etc. in which theunit is mounted in the most scientific and eiilcient manner.

Another object of my invention is to construct a unit in the form of apanel adapted to be set with perfect safety flush or adjacent theceiling or wall surface of a room with the assurance that the maximumheat generated by the panel 5 will be transmitted or radiated into theroom in the most economical and eiilcient manner. Since the unit isthoroughly insulated as before stated, the above method of mounting ofthe panel can be carried out with perfect safety from the stand- 50point of fire hazards. Also the construction of the panel unit is suchthat it provides efficient insulation against any external heat it isdesiredto exclude, thus providing a source of manifold insulation aswell as a heat producing medium. 65 The panel may be made of any size,shape or transverse contour with equal facility and according to'therequirements of individual installations.

Instead of the panel, the unit may take the form of a broad system oflamlnations for use over large broad areas such as floors, ceilings andwalls, and comprising layers of material substantially the same as thosecontained in the panel I or strip form of the unit, and with equalsafety and emciency in mounting and operation.

Though ordinarily the heat producing agency of the heating unit is anelectric resistance element, in certain cases as when the panels are tocover a large area, hot water or steampipes may be used instead of theresistance wire, with the same emcient results as to the radiation anddistribution of the heat. I

The broad or large laminated form of construction is to be used overlarge areas where the panel or strip form is not applicable, but wherean economical and eilicient means of providing heat is found desirable.

A further object of the invention is to produce a simple and inexpensivedevice and yet one which will be exceedingly effective for the purposefor which it is designed.

These objects I accomplish by means of such structure and relativearrangement of parts as will fully appear by a perusual of the followingspecification and claims.

In the drawing similar characters of reference indicate correspondingparts in the several views:

Figure 1 is a perspective view of the panel form of my improved electricheating unit showing the same mounted in unitary connection with aspecial form of outlet box.

Figure 2 is a fragmentary enlarged view of the panel with the outlet boxin section and with the various layers of the panel broken away.

Figure 3 is a fragmentary perspective view of a heating unit for usewhen flexibility is desired, as for wrapping conduits and piping of anyform containing liquids, solids or a vacuum, which it is desired to keepwarm or prevent from freezing.

Referring now more particularly to the characters of reference on thedrawing, and particular- 1y at present to Figures 1 and 2, the rigid orpanel form of heating unit comprises a back sheet i of metal of asuitable character, polished or bright on one or both sides, andpossesses certain scientific properties and values of reflection,refraction and thermal insulation in radiant heat energy transfer,diffusion and dissipation. Disposed against the sheet I is the base orstructural member 2 of the panel. This is relatively thick and is ofcellular material having rigidity.

strength, fire resistant properties, as well as high insulating valuesas characteristic features. This material may be one of those of specialcomposition such as those known to the trade as "Thermax", Celotex, orthe like, or it may be ordinary asbestos, cork, or other compositionboards of standard character.

Adhored against the face of the member 2 cpposite the sheet I is apreferably thin dielectric liner 3. This may be a varnished cambric orother treated fabric of suitable character, mica or any other equivalentmaterial possessing properties of known electrical insulation values.This liner serves as an insulation for the panel against the possibilityof the electric current leaking, or the grounding of the resistanceelement of the heat generating unit of the panel, which is superimposedon the dielectric liner.

This heating unit comprises an envelope formed of a pair of sheets I andI of asbestos, mica or equivalent insulating material, between which isdisposed the resistance element or grid 6. This is preferably ofenameled wire and is laid so as to extend over substantially the entirearea of the panel. The envelope sheets 4 and 5 are adhered together by aflexible thermoplastic moistureproof substance of suitable materialwhich hermetically seals and insulates the bare or enameled wire in theenvelope.

The envelope is preferably covered by a surface sheet 1 of the samegeneral character as the sheets I and 5, which may be finished in anysuitable manner and color to harmonize with the wall or ceiling finish,since this surface of the panel is the one exposed in the room to beheated. Said surface sheet is of such a nature that when affixed to anemissory surface, such as that of the heat generating unit, it possessescertain properties of radiation, heat transfer, refraction anddiffusion.

With a heating panel constructed as above a maximum amount of "heatloss" or thermal radiation from the resistance wire will be radiatedfrom the outer or room exposed surface of the panel, due largely to theuse of the polished or bright metal sheet I at the back of the panel,and which possesses the aforementioned properties of heat reflection,refraction, and thermal insulation values. It may here be noted thatwhile I show and describe this metal sheet as being at the back of thepanel, this position is not absolute, since it may possibly be disposedon the front side of the base layer I. Said layer 2 not only forms thestructural member of the panel, enabling the same to be easily mountedin place against the studs or ceiling joists, but serves as a heat andcold insulator as well as being fire resistant.

The entire panel being fire resistant, and the resistance wire beingcompletely insulated from the other parts of the panel, the hazards areeliminated making it perfectly safe to mount the panel against thewoodwork of the building.

To connect the resistance wire 6 to a source of current I preferablyprovide a special form of outlet box 8, which is recessed in the panelat one end as shown and which carries spaced terminal posts 8 in thebottom. The ends of the resistance wire 8 are connected to the posts aswell as the supply wires l which lead to the main current line of thebuilding etc.

In the form of the invention disclosed in Fig ure 3 the base member 2 isdispensed with and the unit is made in the form of a flexible strip asshown, adapted to be wrapped spirally about heating pipes to retain andadd to the heat therein. Such strip therefore comprises a metalrefleeting strip la, a dielectric strip 3a, envelope strips in. and acontaining the wire or ribbonlike resistance element Ba. and theexterior cover strip in. All these strips have the same properties asthose of the panel type of device and with the strip Ia disposed againstthe pipe, the maximum heat generated by the heating ribbon la will beradiated inwardly of the pipe.

From the foregoing description it will be readily seen that I haveproduced such a device as substantially fulfills the objects of theinvention as set forth herein.

While this specification sets forth in detail the present and preferredconstruction of the device, still in practice such deviations from suchdetail may be resorted to as do not form a departure from the spirit ofthe invention, as defined by the appended claims.

Having thus described my invention, what I claim as new and useful anddesire to secure by Letters Patent is:

1. A theme-radiant heating device in panel form comprising a base memberof relatively thick and rigid cellular heat insulating material. aheating unit disposed adjacent one face of the member and comprising aninsulating envelope and an electric resistance element hermeticallysealed therein, an outlet box recessed into the panel at one end, andspaced terminal posts in the box connected to the ends of the resistanceelement; said ends projecting into the box from between the walls of theenvelope.

2. A structure as in claim 1, in which the box is substantially equal inwidth to the thickness of the panel and includes side plates overlappingand secured to the opposite outer surfaces of the panel.

EDWARD F. WACH.

